Commercially available herbicide compositions include a very large variety of active herbicide compounds. Herbicide compositions can be prepared from a variety of different types of precursor compositions, and can be commercially available and used in a variety of different types of compositions, including compositions referred to as wettable powders, water dispersible granules, granules, aqueous solutions, water soluble powders, emulsifiable concentrates, oil-based flowables, concentrated emulsions, suspo-emulsions, emulsions, suspensions, suspension concentrates, mixtures, dispersions, and microemulsions, as well as others. Any of these different types of compositions may have different advantages or disadvantages depending on what type of active ingredients the herbicide includes.
Examples of just a few available active herbicide compounds include those of the general class known as phenoxy herbicides, e.g., 2,4-dichlorophenoxyacetic acid (known as 2,4-D), MCPA acid, MCPP acid; those of the general class known as pyridine herbicides, (e.g., triclopyr, fluoroxypyr); those of the general class of benzoic acid herbicides, (e.g., dicamba acid); those of the general class of aryloxy phenoxy propionic acid herbicides, (e.g., fluazifop acid and quizolofop acid); water-insoluble diphenyl ether type herbicides (e.g., oxyfluorfen or acifluorfen); glyphosate compounds (e.g., in the IPA salt form); imidizole herbicide compounds (e.g., imazapyr or imazaquin); as well as others.
Active herbicide ingredients such as these and others can be prepared from and used in the form of solid and liquid compositions including, as mentioned above, different forms of emulsions, suspensions, suspension concentrates, mixtures, dispersions, and microemulsions, etc. With regard to the liquid forms, the active ingredient (herbicide compound) is generally suspended or dissolved in a liquid, with the active herbicide compound taking the chemical form of a salt or ester, depending on which form is either soluble or suspendable in such a liquid composition. Most herbicide compositions are prepared from an ester or salt form of a herbicide compound, or are prepared using a step to convert an acid form of a herbicide compound to a salt or an ester to be either miscible in water or emulsifiable in water for application, often with the assistance of organic solvent.
With microemulsion compositions in particular, earlier microemulsion work typically included the use of herbicide compounds in forms other than their acid forms, e.g., ester or salt forms, because the salt or ester forms were considered to be most easily dispersed or suspended in a microemulsion. Typical microemulsions also incorporated organic solvents to effect suspension or dissolution of the herbicide compound.
New forms of effective herbicide compositions are always desirable, especially those that show advantages in processing, application, environmental profile (e.g., volatility), or efficacy. And there is always a desire to prepare herbicide compositions that reduce or eliminate organic solvents.